9
Answer: BSet 1: Trigonometry (Advanced)
Explanation
PROBLEM
If sin(theta) = 6/10 and theta is in the first quadrant, find cos(theta).
If sin(theta) = 6/10 and theta is in the first quadrant, find cos(theta).
A.
10/8
B.✓ Correct
8/10
C.
6/8
D.
6/10
Detailed Explanation
Choice B is the best answer. cos squared = 1 - sin squared = 1 - 36/100 = 64/100. cos = 8/10
Why others are wrong:
A: 10/8 is incorrect because it does not satisfy the equation.
C: 6/8 is incorrect because it does not satisfy the equation.
D: 6/10 is incorrect because it does not satisfy the equation.